The invention relates to an axle support for a vehicle, in particular for a motor vehicle, and to a method for the production of an axle support for a vehicle, in particular for a motor vehicle.
Such axle supports, also referred to as subframe or chassis underframe, are generally known and are typically comprised of two longitudinal members which are oriented substantially in vehicle length direction, when the axle support is installed, and which are connected to one another by at least one cross member oriented substantially in vehicle transverse direction. Surface protection for axle supports of steel material is usually realized by cathodic electro-deposition. When regions of the axle support, such as especially a leading cross member of the axle support, as viewed in travel direction, lie in the jet stream of particles that have been hurled up by the vehicle tires, particular surface protection measures are taken in order to protect this axle support region from damage. It is hereby generally known to attach for example protective plastic shells on the axle support. Furthermore, a very expensive complete galvanization of the axle support is generally known. Individually galvanized parts are, however, not welded, because the complex geometries of the formed components do not enable zinc fumes generated during welding to escape and cause gas pockets in the weld seams. Such gas pockets form pores in weld seams which in turn result in excessive variations of the service life of the weld seams and thus are unsuitable for use in safety components, as axle supports are considered.
An axle support for motor vehicles is already known from the generic DE 10 2007 030 929 B9 and includes two longitudinal members and two cross members connecting the two longitudinal members with one another, wherein both cross members as well as the longitudinal members can be made from sheet metal shells welded to one another. In particular the leading cross member, as viewed in travel direction, should be formed from a leading and a trailing sheet metal shell, wherein a leading sheet metal shell is formed by at least three metal sheets, welded to one another, such that the leading sheet metal shell has two outer sections which are connected to the longitudinal members, with the outer sections being interconnected by a middle section having a smaller sheet metal thickness or is made of material with less strength than the outer sheet metal parts. This leading sheet metal shell is thus manufactured as tailored blank sheet metal component to provide a cross member with optimal weight and material properties. The same applies analogously also for the region of the longitudinal members and the region of the second cross member. In all such cross members and longitudinal members, made in shell construction, pre-coated metal sheets may further be used, i.e. metal sheets which are surface-coated with a zinc alloy or aluminum alloy. This results, however, in the afore-mentioned drawbacks, namely gas pockets and thus pore formation in the weld seams, when such galvanized individual parts are welded. This may cause a reduction in service life of the weld seams.
The use of a tailored blank sheet metal components, as described above in connection with the DE 10 2007 030 929 B9, is generally known. This involves the use of several planar sheet metal blanks or sheet metal plates which are welded to one another and tailored to suit the respective technical application. The individual sheet metal blanks have different sheet metal thicknesses and/or are made of materials with different strengths. The desired formed components are then manufactured from these planar tailored blank sheet metal plates through forming. The individual sheet metal blanks of the tailored blank component are hereby arranged in relation to one another such that the shaped formed component has in precisely predefined regions the respective sheet metal blank that has the desired wall thickness or material strength for this region. Thus, component regions that are less exposed to stress are for example formed by sheet metal blanks of lesser sheet metal thickness than those component regions that are exposed to greater stress. In this way, components are produced of dimensions and constructions suited to stress and having optimum overall weight, as this is the case in DE 10 2007 030 929 B9.
There are different tailored blank types or methods, such as for example TRB (Tailored Rolled Blank), in which the sheet metal strip (coil) is rolled cold yet again to produce different metal sheet thicknesses. In contrast thereto, the tailored welded blank process (TWB process) involves a welding of the individual metal sheet blanks to one another. This is normally realized in butt joint configuration by laser welding.